Move kernel_vm_end's declaration to pmap.h; add a comment regarding the

synchronization of access to kernel_vm_end.

sys/vm/pmap.h

@@ -89,6 +89,11 @@ typedef struct pmap_statistics *pmap_statistics_t;
 struct proc;
 struct thread;
 
+/*
+ * Updates to kernel_vm_end are synchronized by the kernel_map's system mutex.
+ */
+extern vm_offset_t kernel_vm_end;
+
 extern	int	 pmap_pagedaemon_waken;
 
 #ifdef __alpha__

sys/vm/vm_kern.h

@@ -75,6 +75,4 @@ extern vm_map_t clean_map;
 extern vm_map_t exec_map;
 extern u_int vm_kmem_size;
 
-extern vm_offset_t kernel_vm_end;
-
 #endif				/* _VM_VM_KERN_H_ */